Disposable absorbent article

ABSTRACT

A rear elastic area formed by a rear waist region with rear waist elastic members stretchable laterally across the rear waist region. A front elastic area formed by a front waist region with front waist elastic members stretchable laterally across the front waist region. The rear waist region and the front waist region are capable of stretching or contracting in unison. A greater number of rear waist elastic members than front waist elastic members are provided. The rear elastic area is broader than the front elastic area with respect to the longitudinal direction of the diaper body. The body-hugging capability of the diaper body at the rear waist side of the wearer is increased so that the diaper body is prevented from slipping down. This configuration reduces constructive feeling by ensuring that the diaper body is not excessively tight at the front waist side of the wearer.

TECHNICAL FIELD

The present invention relates to a disposable absorbent article that maybe used, for example, by an adult as an incontinence product or othersuch purposes.

BACKGROUND OF THE INVENTION

A conventional disposable absorbent article of this type has anabsorbent article body that typically comprises an absorbent pad and acover sheet provided over the outer surface of the absorbent pad, i.e.the surface that faces the garment of the wearer. The absorbent padcomprises a liquid-permeable topsheet, a liquid-impermeable backsheet,and an absorbent core disposed therebetween. The absorbent article bodyhas a rear waist region, a crotch region, and a front waist region,which are integrally arranged in the longitudinal direction from rear tofront. The absorbent article body is pre-formed in a briefs-like shapeby joining each side edge portion of the rear waist region and thecorresponding side edge portion of the front waist region so as to forma waist opening and a pair of leg openings. Waist opening elasticmembers are provided circumferentially around the waist opening. Therear waist region and the front waist region are respectively providedwith rear waist elastic members and front waist elastic members (anexample is shown in Japanese Patent Laid-open No. 2002-165820).

However, a disposable absorbent article having the configurationdescribed above is formed in such a briefs-like shape that the rearwaist elastic members and the front waist elastic members are positionedalmost exactly opposite each other in nearly the same number and provideapproximately the same stretchability ratio. Therefore, should thetensile stress of the rear waist elastic members and the front waistelastic members be insufficient, there is the possibility of the briefsslipping down due to a poor body-hugging capability.

Consequently, in order to increase the body-hugging capability andprevent slippage and leakage, manufacturers of such articles generallyprovide the absorbent article body with a substantial tensile stress.This, however, may give the wearer an unnecessarily strong constrictingfeeling. Particularly when the wearer has a bulging lower abdomen, thewearer may feel it too tight at the lower abdomen.

Should the wearer tend to slouch due to advanced age or other reasons,the rear waist elastic members and the front waist elastic membershaving the same tensile stress may result in the absorbent article bodyslipping down from the buttock.

In order to solve the above problems, an object of the invention is toprovide a disposable absorbent article that has superior body-huggingcapability, is free from the problem of slippage, and has reducedconstrictiveness.

DISCLOSURE OF THE INVENTION

A disposable absorbent article according to the present inventionincludes an absorbent article body comprising a liquid-permeabletopsheet, a liquid-impermeable backsheet, an absorbent core disposedbetween the liquid-permeable topsheet and the liquid-impermeablebacksheet, and a cover sheet attached to the outer surface of theliquid-impermeable backsheet. The aforementioned absorbent article bodyhas a rear waist region, a crotch region, and a front waist region,which are integrally arranged in the longitudinal direction of theabsorbent article body. The rear waist region and the front waist regionare adapted to be respectively located at the rear and front waist sideof the wearer. The crotch region has leg opening portions at bothlateral side edges thereof. By joining each side edge portion of therear waist region and the corresponding side edge portion of the frontwaist region, a waist opening becomes formed around the waist of thewearer and a pair of leg openings become formed around the upper thighsof the wearer. The absorbent article body also has one or more waistopening elastic members extending circumferentially around the waistopening, a plurality of rear waist elastic members that are stretchablein the widthwise direction of the absorbent article body, and aplurality of front waist elastic members that are stretchable in thewidthwise direction of the absorbent article body. The aforementionedrear waist elastic members form a rear elastic area in the rear waistregion. The aforementioned front waist elastic members form a frontelastic area in the front waist region. A greater number of rear waistelastic members are provided than front waist elastic members. The rearelastic area is broader than the front elastic area with respect to thelongitudinal direction of the absorbent article body. By providing therear waist region and the front waist region respectively with rearwaist elastic members and front waist elastic members, all of which arestretchable in the widthwise direction of the absorbent article body, soas to form a rear elastic area and a front elastic area, the rear waistregion and the front waist region are enabled to stretch or contract inunison at the rear and front of the wearer, and the body-huggingcapability of the disposable absorbent article around the waist isimproved. Furthermore, by providing a greater number of rear waistelastic members than front waist elastic members and making the rearelastic area broader than the front elastic area with respect to thelongitudinal direction of the absorbent article body, the body-huggingcapability of the disposable absorbent article at the rear waist side ofthe wearer is increased so that the disposable absorbent article isprevented from slipping down, while constrictive feeling given by thedisposable absorbent article is reduced so as not to be excessivelytight at the front waist side of the wearer.

According to another feature of the invention, the rear waist elasticmembers of the disposable absorbent article are arrange so that thedistance between each rear waist elastic member and its adjacent rearwaist elastic member is nearly equal to the distance between each frontwaist elastic member and its adjacent front waist elastic member andthat, when each side edge portion of the rear waist region and thecorresponding side edge portion of the front waist region are joined,both ends of some number of rear waist elastic members are respectivelyconnected to the ends of the corresponding front waist elastic members.By arranging the rear waist elastic members of the disposable absorbentarticle so that the distance between each rear waist elastic member andits adjacent rear waist elastic member is nearly equal to the distancebetween each front waist elastic member and its adjacent front waistelastic member and that, when each side edge portion of the rear waistregion and the corresponding side edge portion of the front waist regionare joined, both ends of some number of rear waist elastic members arerespectively connected to the ends of the corresponding front waistelastic members, the rear waist region and the front waist region areenabled to be closely joined to each other around the entire waist ofthe wearer and thereby prevent the disposable absorbent article fromslipping down.

According to yet another feature of the invention, the distance betweenthe waist opening elastic members of the disposable absorbent articleand the portion of the rear waist elastic members closest to the waistopening elastic members is nearly equal to the aforementioned distancebetween each rear waist elastic member and its adjacent rear waistelastic member. With the configuration as above, wherein the distancebetween the waist opening elastic members and the portion of the rearwaist elastic members closest to the waist opening elastic members isnearly equal to the distance between each rear waist elastic member andits adjacent rear waist elastic member, the waist opening elasticmembers and the rear waist elastic members are arranged evenly in therear waist side of the wearer. This configuration makes the entire rearwaist region serves as an elastic area so that the entire rear waistregion, which extends from the elastic area formed of the waist openingelastic members to the rear elastic area, be able to stretch in unison.Therefore, the disposable absorbent article is provided with a closerfit so as to be more reliably prevented from slipping down.

According to yet another feature of the invention, the distance betweenthe waist opening elastic members of the disposable absorbent articleand the portion of the rear waist elastic members closest to the waistopening elastic members is nearly equal to the distance between thewaist opening elastic members and the portion of the front waist elasticmembers closest to the waist opening elastic members, and the absorbentcore is arranged so as not to overlap the front elastic area whileoverlapping at least a part of the rear elastic area. As the distancebetween the waist opening elastic members and the portion of the rearwaist elastic members closest to the waist opening elastic members isnearly equal to the distance between the waist opening elastic membersand the portion of the front waist elastic members closest to the waistopening elastic members, all of the waist opening side of the rear waistregion and the front waist region serve as an elastic area so that therear waist region and the front waist region are closely joined to eachother around the entire waist of the wearer and thereby prevent thedisposable absorbent article from slipping down. Furthermore, as theabsorbent core overlaps at least a part of the rear elastic area, theabsorbent core closely fits at the rear waist side of the wearer andprevents leakage of urine or other discharged fluids without theabsorbent core extending into the rear waist region any further thannecessary.

According to yet another feature of the invention, the portion of thefront waist elastic members of the disposable absorbent article closestto the leg opening portions is located closer to the leg openingportions than is the portion of the rear waist elastic members closestto the leg opening portions, and the absorbent core is arranged so asnot to overlap the rear elastic area while overlapping at least a partof the front elastic area. As the portion of the front waist elasticmembers closest to the leg opening portions 16 is located closer to theleg opening portions than is the portion of the rear waist elasticmembers closest to the leg opening portions, the disposable absorbentarticle is prevented from being too tight at the front waist side of thewearer. Furthermore, as the absorbent core is provided so as to overlapat least a part of the front elastic area, the absorbent core closelyfits at the front waist side of the wearer and prevents leakage withoutthe absorbent core extending into the front waist region any furtherthan necessary.

According to yet another feature of the invention, the distance betweenthe leg opening portions of the disposable absorbent article and theportion of the rear waist elastic members closest to the leg openingportions is nearly equal to the distance between the leg openingportions and the portion of the front waist elastic members closest tothe leg opening portions, and the absorbent core is arranged so as notto overlap the rear elastic area while overlapping at least a part ofthe front elastic area. As the distance between the leg opening portionsand the portion of the rear waist elastic members closest to the legopening portions is nearly equal to the distance between the leg openingportions and the portion of the front waist elastic members closest tothe leg opening portions, all of the waist opening side of the rearwaist region and the front waist region serve as an elastic area so thatthe rear waist region and the front waist region are closely joined toeach other around the entire waist of the wearer. Furthermore, as theabsorbent core overlaps at least a part of the front elastic area, theabsorbent core closely fits at the front waist side of the wearer andprevents leakage without the absorbent core extending into the frontwaist region any further than necessary.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a practical example of a disposable absorbentarticle according to a first embodiment of the present invention;

FIG. 2 is a vertical sectional view of the aforementioned disposableabsorbent article;

FIG. 3 is a perspective of the disposable absorbent article;

FIG. 4 is a perspective of another practical example of the same;

FIG. 5 is a perspective of yet another working example of the disposableabsorbent article;

FIG. 6 is a perspective of a disposable absorbent article according to asecond embodiment of the present invention;

FIG. 7 is a perspective of a disposable absorbent article according to athird embodiment of the present invention; and

FIG. 8 is a perspective of another working example of the disposableabsorbent article according to the third embodiment of the presentinvention.

PREFERRED EMBODIMENT OF THE INVENTION

Next, the configuration of a disposable absorbent article according tothe first embodiment of the present invention is explained hereunder,referring to FIGS. 1 through 3.

The disposable absorbent article shown in FIG. 1 is, for example, adisposable paper diaper and has a diaper body 1 serving as an absorbentarticle body. The diaper body 1 is formed from the flat-out state shownin FIG. 1 into a briefs-like shape shown in FIG. 3 so that the wearer,who may have health problems or suffer from incontinence, can put itaround the portion of the body from the rear waist to the front waist.The diaper body 1 has a layered structure consisting of aliquid-permeable topsheet 2 that can pass liquid, a liquid-impermeablebacksheet 3 that does not allow liquids to pass, an absorbent core 4that is disposed between the liquid-permeable topsheet 2 and theliquid-impermeable backsheet 3 and capable of absorbing liquids, and acover sheet 5 bonded to the outer surface of the liquid-impermeablebacksheet 3.

The liquid-permeable topsheet 2 and the liquid-impermeable backsheet 3are bonded to each other along the outer edges with a bonding agent orany other appropriate means, with the absorbent core 4 sealed betweenthe two sheets.

The liquid-permeable topsheet 2 is made of a sheet material such as awoven fabric, nonwoven fabric, porous film, or synthetic resin. To bemore specific, the liquid-permeable topsheet 2 is made of a sheetmaterial that is liquid permeable as well as gas permeable and has asimilar texture to underwear so that the liquid-permeable topsheet 2facilitates passage of discharged fluids, such as urine, to theabsorbent core 4 while avoiding discomfort for the wearer in spite ofbeing worn next to the skin.

The liquid-impermeable backsheet 3 is made of a sheet material, such aspolyethylene or any other appropriate synthetic resin, that is gaspermeable but impermeable to liquid so as to prevent urine or otherdischarged fluids from soiling clothes, such as underwear, or bedsheets.

The absorbent core 4 is formed in a sheet-like shape of a material thatcontains pulp or a similar material as the principal component, as wellas such other materials as a super absorbent polymer so that theabsorbent core 4 has sufficient capability to absorb urine or otherdischarged fluids.

As shown in FIG. 1, the liquid-permeable topsheet 2, theliquid-impermeable backsheet 3, and the absorbent core 4 all have arectangular shape and are placed at the approximate center of the coversheet 5 so that the long sides of the rectangular shape extend in thelongitudinal direction of the diaper body 1.

As shown in FIGS. 1 and 2, the cover sheet 5 is larger than theliquid-permeable topsheet 2, the liquid-impermeable backsheet 3, or theabsorbent core 4. The cover sheet 5 is formed of an inner sheet 11 andan outer sheet 12, which are layered one on top of the other andintegrally bonded to each other. Both the inner sheet 11 and the outersheet 12 are gas permeable but impermeable to liquid. The outer surfaceof the liquid-impermeable backsheet 3 is bonded to the inner sheet 11with a bonding agent or any other appropriate means.

The cover sheet 5 consists of a rear waist region 13, a crotch region14, and a front waist region 15, which are integrally arranged, whenviewed in the flat-out state, in the longitudinal direction of thediaper body 1. When in use, the rear waist region 13 and the front waistregion 15 are respectively located at the rear and front waist side ofthe wearer. As a whole, the cover sheet 5 has a generally rectangularshape that is symmetrical with respect to the center line that extendsin the longitudinal direction. Each lateral side edge portion of thecrotch region 14 is cut out in an arc so as to form a leg openingportion 16.

The liquid-permeable topsheet 2, the liquid-impermeable backsheet 3, andthe absorbent core 4 are positioned so as to extend in the longitudinaldirection of the cover sheet 5 of the diaper body 1 so that thelongitudinal center line of the liquid-permeable topsheet 2, theliquid-impermeable backsheet 3, and the absorbent core 4 essentiallycorresponds to the longitudinal center lines of the rear waist region13, the crotch region 14, and the front waist region 15.

The rear waist region 13 of the cover sheet 5 of the diaper body 1 islocated at one of the longitudinal ends of the diaper body 1 as viewedin the flat-out state. When the diaper body 1 is folded to anappropriate degree from the flat-out state, the rear waist region 13becomes the portion that will be located at the buttock of the wearer. Arear waist bonding portion (not shown) is formed along each side edge ofthe rear waist region 13.

The crotch region 14 of the diaper body 1 is located at the longitudinalmiddle of the diaper body 1 as viewed in the flat-out state, locatedbetween the rear waist region 13 and the front waist region 15 as anintegral, continuous body therewith. When the diaper body 1 is folded toan appropriate degree from the flat-out state, the crotch region 14becomes the portion that will be located at the crotch of the wearer.

The front waist region 15 of the diaper body 1 is located at the otherlongitudinal end of the diaper body 1 as viewed in the flat-out state,i.e. the opposite end of the rear waist region 13, as an integral,continuous body with the crotch region 14. When the diaper body 1 isfolded to an appropriate degree from the flat-out state, the front waistregion 15 becomes the portion that will be located at the abdomen of thewearer. The front waist region 15 has an approximately rectangular shapelonger in the lateral direction of the diaper body 1 than thelongitudinal direction, the same configuration as the rear waist region13.

A front waist bonding portion (not shown) for attachment to thecorresponding rear waist bonding portion of the rear waist region 13 isformed near each side edge of the front waist region 15. By attachingeach front waist bonding portion to the corresponding rear waist bondingportion, a waist opening 21 is defined by the rear waist region 13 andthe front waist region 15 around the waist of the wearer while a pair ofleg openings 22 are defined by the two leg opening portions 16. Thus, asshown in FIG. 3, the diaper body 1 is formed into a briefs-like shape.

As shown in FIG. 1, between the inner sheet 11 and the outer sheet 12,the rear waist region 13 and the front waist region 15 are respectivelyprovided with a plurality of waist opening elastic members 23 (forexample three elastic members). The waist opening elastic members 23 aremade of an elastic material, such as elastic threads, and affixed to therear waist region 13 and the front waist region 15 with a bonding agentor any other appropriate means, in such a state as to be stretchedlaterally across the rear waist region 13 and the front waist region 15.The waist opening elastic members 23 are arranged at equal intervals G1(G1 may desirably range between 2 mm and 7 mm) in the longitudinaldirection of the diaper body 1. In other words, when the diaper body 1is in the briefs-like shape shown in FIG. 3, the waist opening elasticmembers 23 extend circumferentially around the waist opening 21. Thewaist opening elastic members 23 thus provided give elasticity to nearlythe entire area of the rear waist region and the front waist region, inother words nearly the entire waist of the wearer.

A plurality of rear waist elastic members 24 are provided between theinner sheet 11 and the outer sheet 12 of the rear waist region 13. Therear waist elastic members 24 are made of an elastic material, such aselastic threads, and affixed to the rear waist region 13 with a bondingagent or any other appropriate means, in such a state as to be stretchedlaterally across the rear waist region 13. The rear waist elasticmembers 24 are arranged at equal intervals (desirably 2 to 6 members per5 cm) in the longitudinal direction of the diaper body 1. In the case ofthe present embodiment, the rear waist elastic members 24 consist ofseven elastic members that are arranged at intervals G2, wherein G2ranges from 8 mm to 20 mm. Therefore, the rear waist elastic members 24are arranged at wider intervals than are the waist opening elasticmembers 23. In other words, the waist opening elastic members 23 arespaced more closely to one another than are the rear waist elasticmembers 24 and can be expressed as G1<G2.

As the rear waist elastic members 24 are stretchable laterally acrossthe rear waist region 13, the rear waist region 13 can be stretched inwidthwise direction of the diaper body 1 by stretching the rear waistelastic members 24. As shown in FIG. 3, a rear elastic area 25 is formedin the rear waist region 13 by the rear waist elastic members 24.

It is desirable that the tensile stress of the rear elastic area 25range from 1.5 to 2.0 N. In order to achieve such a stress, each rearwaist elastic member 24 may desirably be stretched with a tensile stressof 0.08 to 2.5 N and a 1.5-to 3.0-fold stretching ratio.

The distance G3 between the waist opening elastic members 23 and theportion of the rear waist elastic members 24 that is closest to thewaist opening elastic members 23, in other words the uppermost rearwaist elastic member 24 as viewed in FIG. 3, is greater than thedistance G2 between each rear waist elastic member 24 and its adjacentrear waist elastic member 24 (G2<G3).

A plurality of front waist elastic members 26 are provided between theinner sheet 11 and the outer sheet 12 of the front waist region 15.

The front waist elastic members 26 are made of an elastic material, suchas elastic threads, and affixed to the front waist region 15 with abonding agent or any other appropriate means, in such a state as to bestretched laterally across the front waist region 15. The front waistelastic members 26 are arranged at equal intervals (desirably 2 to 6members per 5 cm) in the longitudinal direction of the diaper body 1. Inthe case of the present embodiment, the front waist elastic members 26consist of five elastic members that are arranged at intervals G4,wherein G2 ranges from 8 mm to 20 mm. Therefore, there are fewer frontwaist elastic members 26 than rear waist elastic members 24, and thefront waist elastic members 26 are arranged at wider intervals than arethe waist opening elastic members 23. In other words, a greater numberof rear waist elastic members 24 are provided than front waist elasticmembers 26, and the waist opening elastic members 23 are spaced moreclosely to one another than are the front waist elastic members 26.

As the front waist elastic members 26 are stretchable laterally acrossthe front waist region 15, the front waist region 15 can be stretched inwidthwise direction of the diaper body 1 by stretching the front waistelastic members 26. A front elastic area 27 is formed in the front waistregion 15 by the front waist elastic members 26.

It is desirable that the tensile stress of the front elastic area 27range from 1.0 to 1.5 N. In order to achieve such a stress, each frontwaist elastic member 26 may desirably be stretched with a tensile stressof 0.08 to 2.5 N and a 1.5-to 3.0-fold stretching ratio.

The front waist elastic members 26 are arranged so that the portionclosest to the waist opening elastic members 23, i.e. the front waistelastic member 26 that is closest to the waist opening 21, correspond tothe portion of the rear waist elastic members 24 second-closest to thewaist opening elastic members 23, in other words the second-from-the-toprear waist elastic member 24 as viewed in FIG. 3, when the diaper body 1is formed into the briefs-like shape. Therefore, when the diaper body 1is formed into the briefs-like shape, the two lateral ends of the frontwaist elastic member 26 closest to the waist opening 21 are connected tothe respective lateral ends of the second-from-the-top rear waistelastic member 24 as viewed in FIG. 3.

The distance G4 between each front waist elastic member 26 and itsadjacent front waist elastic member 26 is nearly equal to the distanceG2 between each rear waist elastic member 24 and its adjacent rear waistelastic member 24 (G2≈G4). Therefore, the front elastic area 27 isshorter in the longitudinal direction of the diaper body 1 than the rearelastic area 25. In other words, the rear elastic area 25 is broaderthan the front elastic area 27 with respect to the longitudinaldirection of the diaper body 1. As a result, when the diaper body 1 isformed into the briefs-like shape as shown in FIG. 3, the ends of thefront waist elastic members 26 are respectively connected to the ends ofthe second-through-fifth-from-the-top rear waist elastic members 24 asviewed in FIG. 3.

The stretchability of the front waist elastic members 26 shoulddesirably be adjusted so that the stretchability ratio of the frontelastic area 27 does not exceed that of the rear elastic area 25. Thiscan be achieved by, for example, using a different material from that ofthe rear waist elastic members 24 or the same material with differentcharacteristics, such as thickness.

Leg opening elastic members (not shown) made of elastic threads or otherappropriate material are provided, in a stretched state, between theinner sheet 11 and the outer sheet 12 of the cover sheet 5, near eachleg opening portion 16. As a result of the provision of the leg openingelastic members, each leg opening portion 16 is shirred so as to beelastic both in the longitudinal direction and the widthwise directionof the diaper body 1.

Next, the function and effects of the first embodiment described aboveare explained hereunder.

To use, the diaper body 1 is formed into a briefs-like shape shown inFIG. 3 so that it can be worn like underpants.

By providing a plurality of rear waist elastic members 24 so as to bestretchable in the widthwise direction of the diaper body 1, a rearelastic area 25 is formed in the rear waist region 13. By providing aplurality of front waist elastic members 26 so as to be stretchable inthe widthwise direction of the diaper body 1, a front elastic area 27 isformed in the front waist region 15. Therefore, the rear waist region 13and the front waist region 15 are capable of stretching or contractingin unison at the rear and front of the wearer so that the body-huggingcapability of the diaper body 1 around the waist is improved.

By providing a greater number of rear waist elastic members 24 than thefront waist elastic members 26 and forming the rear elastic area 25 soas to be broader than the front elastic area 27 with respect to thelongitudinal direction of the diaper body 1, the diaper body 1 isprovided with a closer fit at the rear waist side of the wearer andthereby prevented from slipping down. This is especially effective for awearer of advanced age who tends to slouch. While having these effects,the configuration described above reduces constrictive feeling given tothe wearer by ensuring that the diaper body 1 is not excessively tightat the front waist side of the wearer.

The distance G2 between each rear waist elastic member 24 and itsadjacent rear waist elastic member 24 is nearly equal to the distance G4between each front waist elastic member 26 and its adjacent front waistelastic member 26. Furthermore, when each side edge portion of the rearwaist region 13 is joined to the corresponding side edge portion of thefront waist region 15, the ends of the second-through-fifth-from-the-toprear waist elastic members 24 as viewed in FIG. 3 are respectivelyconnected to the ends of the front waist elastic members 26. Thisconfiguration ensures that the rear waist region 13 and the front waistregion 15 are closely joined to each other around the entire waist ofthe wearer and thereby prevents the diaper body 1 from slipping down.

The waist opening elastic members 23 are arranged so that the distanceG1 between each waist opening elastic member 23 and its adjacent waistopening elastic member 23 are shorter than the distance G4 between eachfront waist elastic member 26 and its adjacent front waist elasticmember 26. Thus arranging the waist opening elastic members 23 increasesthe body-hugging capability of the diaper body 1 around the waist of thewearer, thereby increasing reliability and more reliably preventing thediaper body 1 from slipping down, holds down production costs by keepingthe numbers of elastic members required for the rear waist region 13 andthe front waist region 15 to a minimum, and also limits the tensilestress of the rear waist region 13 and the front waist region 15 to anappropriate, sufficient degree so as not to apply excessive constrictionto the wearer.

An insufficient tensile stress, i.e. less than 1.0 N, of the rearelastic area 25 or the front elastic area 27 may cause the diaper body 1to slip down the wearer's body after the wearer urinates, while atensile stress greater than 2.0 N presents the possibility of excessiveconstriction, resulting in the rear waist elastic members 24 or thefront waist elastic members 26 leaving impressions, in other wordsstretch marks, on the wearer's skin. In the case of the presentembodiment, however, the tensile stress of the rear elastic area 25 andthe tensile stress of the front elastic area 27 are respectively limitedwithin the ranges of 1.5 to 2.0 N and 1.0 to 1.5 N. Therefore, theconstrictive feeling is reduced, and the diaper body 1 is prevented fromslippage, even after the wearer urinates.

Furthermore, making the tensile stress of the rear elastic area 25greater than the tensile stress of the front elastic area 27 providesthe diaper body 1 with a closer fit at the rear waist side.

As shown in FIG. 4, the diaper body 1 according to the first embodimentdescribed above may be provided with a greater number of rear waistelastic members 24 than in the case of the configuration shown in FIGS.1 to 3, with the distance G2 between each rear waist elastic member 24and its adjacent rear waist elastic member 24 reduced. In the case ofthe example shown in FIG. 4, thirteen rear waist elastic members 24 areprovided, with the distance G2 between each rear waist elastic member 24and its adjacent rear waist elastic member 24 reduced to approximatelyhalf of the distance G2 in the configuration shown in FIGS. 1 to 3. Asthis configuration further increases the stretchability of the rearwaist region 13 and thereby provides the rear waist region 13 with acloser fit at the rear waist side of the wearer, it prevents slippage ofthe diaper body 1 more reliably.

Yet another configuration example is shown in FIG. 5, wherein thedistance G3 between the waist opening elastic members 23 and the rearwaist elastic members 24 is nearly equal to the distance G2 between eachrear waist elastic member 24 and its adjacent rear waist elastic member24. This configuration makes the entire rear waist region 13 elastic sothat the entire rear waist region 13, which extends from the elasticarea formed of the waist opening elastic members 23 to the rear elasticarea 25, is able to stretch in unison. Therefore, the diaper body 1 isprovided with a closer fit at the rear waist side and is therefore morereliably prevented from slipping down.

In yet another alternative configuration, the lateral ends of the rearwaist elastic members 24 are positioned alternately with thecorresponding ends of the front waist elastic members 26 instead offorming a continuous line when the diaper body 1 is formed into thebriefs-like shape shown in FIG. 3.

Neither the rear waist elastic members 24 nor the front waist elasticmembers 26 are limited to a particular material; for example, each rearwaist elastic member 24 may have a smaller stretchability ratio thanthat of each front waist elastic member 26, provided that thestretchability ratio of the rear elastic area 25 is greater than that ofthe front elastic area 27. This can be achieved by further increasingthe number of the rear waist elastic members 24 or other appropriatemeans.

Next, the second embodiment of the present invention is explained,referring to FIG. 6.

The embodiment shown in FIG. 6 has a configuration basically similar tothat of the embodiment shown in FIGS. 1 to 3 described above. However, adiaper body 1 according to this embodiment is provided with a pluralityof rear waist elastic members 24, for example eight rear waist elasticmembers, between the inner sheet 11 and the outer sheet 12 of the rearwaist region 13.

Furthermore, a plurality of front waist elastic members 26, for examplesix front waist elastic members, are provided between the inner sheet 11and the outer sheet 12 of the front waist region 15.

The distance G3 between the waist opening elastic members 23 and theportion of the rear waist elastic members 24 that is closest to thewaist opening elastic members 23, in other words the uppermost rearwaist elastic member 24 as viewed in FIG. 6, is nearly equal to thedistance G5 between the waist opening elastic members 23 and the portionof the front waist elastic members 26 that is closest to the waistopening elastic members 23, in other words the uppermost front waistelastic member 26 as viewed in FIG. 6.

As a result, when the diaper body 1 is formed into a briefs-like shapeas shown in FIG. 6, the ends of the front waist elastic members 26 arerespectively connected to the ends of the six uppermost rear waistelastic members 24 as viewed in FIG. 6.

The absorbent core 4 is arranged so as not to overlap the front elasticarea 27 while overlapping the portion of the rear elastic area 25 nearthe leg opening portions 16, for example the three bottommost rear waistelastic members 24 as viewed in FIG. 6.

To use, the diaper body 1 is formed into a briefs-like shape shown inFIG. 6 so that it can be worn like underpants. In this state, all of thewaist opening 21 side of the rear waist region 13 and the front waistregion 15 serve as an elastic area. This configuration ensures that therear waist region 13 and the front waist region 15 are closely joined toeach other around the entire waist of the wearer and thereby preventsthe diaper body 1 from slipping down.

The absorbent core 4 is provided so as to partially overlap the rearelastic area 25. Therefore, even if the absorbent core 4 is positionedso as to extend into the rear waist region 13 and the front waist region15 to the same extent, the absorbent core 4 closely fits at the rearwaist side of the wearer. In other words, the embodiment shown in FIG. 6prevents leakage of urine or other discharged fluids without theabsorbent core 4 extending into the rear waist region 13 any furtherthan necessary.

Next, the third embodiment of the present invention is explained,referring to FIG. 7.

The embodiment shown in FIG. 7 has a configuration basically similar tothat of the embodiment shown in FIGS. 1 to 3 described above. However, adiaper body 1 according to this embodiment is provided with a pluralityof rear waist elastic members 24, for example seven rear waist elasticmembers, between the inner sheet 11 and the outer sheet 12 of the rearwaist region 13.

Furthermore, a plurality of front waist elastic members 26, for examplesix front waist elastic members, are provided between the inner sheet 11and the outer sheet 12 of the front waist region 15.

The front waist elastic members 26 are arranged so that the portion thatis closest to the leg opening portions 16 is located closer to the legopening portions 16 than is the portion of the rear waist elasticmembers 24 that is closest to the leg opening portions 16. In otherwords, the bottommost front waist elastic member 26 as viewed in FIG. 7is located lower than the bottommost rear waist elastic member 24 asviewed in FIG. 7.

Furthermore, the portion that is closest to the waist opening elasticmembers 23, i.e. the uppermost front waist elastic member 26 as viewedin FIG. 7, corresponds to the third-from-the-top rear waist elasticmember 24 as viewed in FIG. 7, when the diaper body 1 is formed into thebriefs-like shape shown in FIG. 7.

Therefore, when the diaper body 1 is formed into a briefs-like shape asshown in FIG. 7, the lateral ends of the five uppermost front waistelastic members 26 as viewed in FIG. 7 are respectively connected to theends of the third-through-seventh-from-the-top rear waist elasticmembers 24 as viewed in FIG. 7.

The absorbent core 4 is arranged so as not to overlap the rear elasticarea 25 while overlapping the portion of the front elastic area 27 nearthe leg opening portions 16, for example the two bottommost front waistelastic members 26 as viewed in FIG. 7.

To use, the diaper body 1 is formed into a briefs-like shape shown inFIG. 7 so that it can be worn like underpants.

As the portion that is closest to the leg opening portions 16 is locatedcloser to the leg opening portions 16 than is the portion of the rearwaist elastic members 24 that is closest to the leg opening portions 16,the diaper body 1 is prevented from being too tight at the front waistside of the wearer.

The absorbent core 4 is provided so as to partially overlap the frontelastic area 27. Therefore, even if the absorbent core 4 is positionedso as to extend into the rear waist region 13 and the front waist region15 to the same extent, the absorbent core 4 closely fits at the frontwaist side of the wearer. In other words, the embodiment shown in FIG. 7prevents leakage without the absorbent core 4 extending into the frontwaist region 15 any further than necessary.

As shown in FIG. 8, the rear waist elastic members 24 and the frontwaist elastic members 26 of the diaper body 1 according to the thirdembodiment described above may be arranged so that the distance G6between the leg opening portions 16 and the portion of the rear waistelastic members 24 that is closest to the leg opening portions 16, i.e.the bottommost rear waist elastic member 24 as viewed in FIG. 8, isnearly equal to the distance G7 between the leg opening portions 16 andthe portion of the front waist elastic members 26 that is closest to theleg opening portions 16, i.e. the bottommost front waist elastic member26 as viewed in FIG. 8. Therefore, all of the leg opening portions 16side of the rear waist region 13 and the front waist region 15 serve asan elastic area so that the rear waist region 13 and the front waistregion 15 are closely joined to each other around the entire waist ofthe wearer.

In any one of the embodiments described above, the tensile stress andthe stretching ratio of each rear waist elastic member 24 and/or frontwaist elastic member 26 may be arbitrarily changed in accordance withthe number or any other characteristics of the rear waist elasticmembers 24 or the front waist elastic members 26, provided that the rearelastic area 25 and the front elastic area 27 respectively have thedesired tensile stresses.

POSSIBLE INDUSTRIAL APPLICATION

As described above, a disposable absorbent article according to theinvention may be used, for example, as a disposable diaper, anincontinence product or other such purposes for an adult.

1. A disposable absorbent article including an absorbent article body which comprises a liquid-permeable topsheet, a liquid-impermeable backsheet, an absorbent core disposed between said liquid-permeable topsheet and said liquid-impermeable backsheet, and a cover sheet attached to the outer surface of said liquid-impermeable backsheet, wherein; said absorbent article body has a rear waist region, a crotch region, and a front waist region, which are integrally arranged in the longitudinal direction of said absorbent article body, said rear waist region and said front waist region adapted to be respectively located at the rear and front waist side of a wearer, and said crotch region has leg opening portions at both lateral side edges thereof; by joining each side edge portion of said rear waist region and the corresponding side edge portion of said front waist region, a waist opening becomes formed around the waist of the wearer and a pair of leg openings become formed around the upper thighs of the wearer; said absorbent article body also has; one or more waist opening elastic members extending circumferentially around said waist opening, a plurality of rear waist elastic members that are stretchable in the widthwise direction of said absorbent article body, and a plurality of front waist elastic members that are stretchable in the widthwise direction of said absorbent article body; said rear waist elastic members form a rear elastic area in said rear waist region; said front waist elastic members form a front elastic area in said front waist region; a greater number of rear waist elastic members are provided than front waist elastic members; and said rear elastic area is broader than said front elastic area with respect to the longitudinal direction of said absorbent article body; said rear waist elastic members are arranged so that the distance between each rear waist elastic member and its adjacent rear waist elastic member is approximately equal to the distance between each front waist elastic member and its adjacent front waist elastic member and that, when each side edge portion of said rear waist region and the corresponding side edge portion of said front waist region are joined, both ends of some but less than all of said rear waist elastic members are respectively connected to the ends of the corresponding front waist elastic members; said distance between said waist opening elastic members and the portion of said rear waist elastic members closest to said waist opening elastic members is approximately equal to the distance between said waist opening elastic members and the portion of said front waist elastic members closest to said waist opening elastic members, and said absorbent core is ranged so as not to overlap said front elastic area while overlapping at least a part of said rear elastic area.
 2. The disposable absorbent article according to claim 1, wherein: the distance between said waist opening elastic members and the portion of said rear waist elastic members closest to said waist opening elastic members is approximately equal to said distance between each rear waist elastic member and its adjacent rear waist elastic member.
 3. A disposable absorbent article including an absorbent article body which comprises a liquid-permeable topsheet, a liquid-impermeable backsheet, an absorbent core disposed between said liquid-permeable topsheet and said liquid-impermeable backsheet, and a cover sheet attached to the outer surface of said liquid-impermeable backsheet, wherein: said absorbent article body has a rear waist region, a crotch region, and a front waist region, which are integrally arranged in the longitudinal direction of said absorbent article body, said rear waist region and said front waist region adapted to be respectively located at the rear and front waist side of a wearer, and said crotch region has leg opening portions at both lateral side edges thereof; by joining each side edge portion of said rear waist region and the corresponding side edge portion of said front waist region, a waist opening becomes formed around the waist of the wearer and a pair of leg openings become formed around the upper thighs of the wearer; said absorbent article body also has; one or more waist opening elastic members extending circumferentially around said waist opening, a plurality of rear waist elastic members that are stretchable in the widthwise direction of said absorbent article body, and a plurality of front waist elastic members that are stretchable in the widthwise direction of said absorbent article body; said rear waist elastic members form a rear elastic area in said rear waist region; said front waist elastic members form a front elastic area in said front waist region; a greater number of rear waist elastic members are provided than front waist elastic members; and said rear elastic area is broader than said front elastic area with respect to the longitudinal direction of said absorbent article body; said rear waist elastic members are arranged so that the distance between each rear waist elastic member and its adjacent rear waist elastic member is approximately equal to the distance between each front waist elastic member and its adjacent front waist elastic member and that, when each side edge portion of said rear waist region and the corresponding side edge portion of said front waist region are joined, both ends of some but less than all of said rear waist elastic members are respectively connected to the ends of the corresponding front waist elastic members; the portion of said front waist elastic members closest to said leg opening portions is located closer to said leg opening portions than is the portion of said rear waist elastic members closest to said leg opening portions, and said absorbent core is arranged so as not to overlap said rear elastic area while overlapping at least a part of said front elastic area.
 4. The disposable absorbent article according to claim 3, wherein: the distance between said waist opening elastic members and the portion of said rear waist elastic members closest to said waist opening elastic members is approximately equal to said distance between each rear waist elastic member and its adjacent rear waist elastic member.
 5. A disposable absorbent article including an absorbent article body which comprises a liquid-permeable topsheet, a liquid-impermeable backsheet, an absorbent core disposed between said liquid-impermeable topsheet and said liquid-impermeable backsheet, and a cover sheet attached to the outer surface of said liquid-impermeable backsheet, wherein; said absorbent article body has a rear waist region, a crotch region, and a front waist region, which are integrally arranged in the longitudinal direction of said absorbent article body, said rear waist region and said front waist region adapted to be respectively located at the rear and front waist side of a wearer, and said crotch region has leg opening portions at both lateral side edges thereof; by joining each side edge portion of said rear waist region and the corresponding side edge portion of said front waist region, a waist opening becomes formed around the waist of the wearer and a pair of leg openings become formed around the upper thighs of the wearer; said absorbent article body also has: one or more waist opening elastic members extending circumferentially around said waist opening, a plurality of rear waist elastic members that are stretchable in the widthwise direction of said absorbent article body, and a plurality of front waist elastic members that are stretchable in the widthwise direction of said absorbent article body; said rear waist elastic members form a rear elastic area in said rear waist region; said front waist elastic members form a front elastic area in said front waist region; a greater number of rear waist elastic members are provided than front waist elastic members; and said rear elastic area is broader than said front elastic area with respect to the longitudinal direction of said absorbent article body; said rear waist elastic members are arranged so that the distance between each rear waist elastic member and its adjacent rear waist elastic member is approximately equal to the distance between each front waist elastic member and its adjacent front waist elastic member and that, when each side edge portion of said rear waist region and the corresponding side edge portion of said front waist region are joined, both ends of some but less than all of said rear waist elastic members are respectively connected to the ends of the corresponding front waist elastic members; the distance separation between said leg opening portions and the portion of said rear waist elastic members closest to said leg opening portions is approximately equal to the distance between said leg opening portions and the portion of said front waist elastic members closest to said leg opening portions, and said absorbent core is arranged so as not to overlap said rear elastic area while overlapping at least a part of said front elastic area.
 6. The disposable absorbent article according to claim 5, wherein: the distance between said waist opening elastic members and the portion of said rear waist elastic members closest to said waist opening elastic members is approximately equal to said distance between each rear waist elastic member and its adjacent rear waist elastic member. 